Uses and misinterpretations of genetics in psychology

An analysis is made of the frequently posed question in psychology of relative contribution of genotypes and environments to phenotypic variation. The illogic of the question, the inappropriateness of the methodology, the inadequacy of the data, and the misleading implications of assertions of proportionality as seen through a sampling of introductory psychology textbooks and referenced publications are outlined. To ask the question of proportionality (of the relative contribution of genotypes and environments in human populations) requires the questioner to make two major erroneous assumptions. The first error is to grant validity to heritability estimates for humans. The second is to conceptualize the genotype as having a range of potential outcomes. An examination is made of these false assumptions.